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Hurricane Linda Discussion Number  29
NWS National Hurricane Center Miami FL       EP122021
1100 PM HST Mon Aug 16 2021
 
Linda has weakened, tonight.  The eyewall has warmed during the past 
6 hours, particularly in the west semicircle, and the convective 
ring has also decreased significantly in coverage, but still 
completely surrounds the 38 n mi diameter eye.  The various 
subjective and objective satellite intensity estimates have all 
decreased, and a blend of these data yields an initial intensity of 
80 kt for this advisory.  It's worth noting that Linda appears to be 
losing its annular cloud pattern which now consists of spiral 
banding features showing up in all quadrants.
 
As research has proven in the past, tropical cyclones that are 
characterized by an annular cloud pattern usually weaken more slowly 
than at a climatological rate in the eastern Pacific. Despite 
currently moving over sub-26C waters, the low shear surrounding 
environment could still offset the negative contribution of 
gradually decreasing sea surface temperatures, at least for the next 
12 hours.  As I mentioned in the previous discussion, Linda may 
still have an outside chance of restrengthening some, or leveling 
off again, while the cyclone moves back over marginally warmer 
water.  Beyond this short term period, Linda is forecast to move 
over much colder waters which should induce a faster weakening as 
the cyclone crosses into the central Pacific.  Global models 
generally agree that Linda will lose organized deep convection in 4 
days and become a post-tropical gale, and this is indicated in the 
official forecast.
 
The initial motion estimate is 265/9 kt.  There is no significant 
change to the previous forecast track or reasoning. Linda should 
continue moving westward for the next 12 hours or so, followed by a 
west-northwestward motion while the hurricane moves around the 
southwest periphery of a mid-tropospheric high located over the 
northeastern Pacific.  The new NHC forecast track is essentially 
just an extension of the previous one and is based primarily on the 
better performing TVCN and HCCA consensus guidance.
 
A 0614 UTC METOP-B scatterometer pass indicated that Linda's wind
radii had contracted in all quadrants, and adjustments were made,
accordingly.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  17/0900Z 17.6N 126.4W   80 KT  90 MPH
 12H  17/1800Z 17.7N 127.8W   80 KT  90 MPH
 24H  18/0600Z 18.1N 129.8W   75 KT  85 MPH
 36H  18/1800Z 18.8N 132.2W   70 KT  80 MPH
 48H  19/0600Z 19.8N 134.9W   65 KT  75 MPH
 60H  19/1800Z 20.7N 137.7W   60 KT  70 MPH
 72H  20/0600Z 21.3N 140.5W   50 KT  60 MPH
 96H  21/0600Z 22.1N 145.8W   40 KT  45 MPH...POST-TROPICAL
120H  22/0600Z 22.7N 149.9W   35 KT  40 MPH...POST-TROPICAL
 
$$
Forecaster Roberts
 
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